Fastener elements and methods of manufacture

ABSTRACT

A male fastener element extends integrally from a planar base and includes a primary engagement hook and a secondary engagement structure (e.g., a hook). The primary engagement hook has a stem portion that is integrally molded with the planar base and that extends from the planar base to a distal end. The primary engagement hook also has an overhang portion that extends from the distal end of the stem portion and that has an underside surface overhanging an open volume for receiving loops. The secondary engagement structure, which is shorter than the primary engagement hook, is disposed immediately adjacent the primary engagement hook and extends from a side surface of the primary engagement hook. The secondary engagement structure extends from the base to a distal end that is disposed, in side view, below the underside surface of the overhang portion of the primary engagement hook.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of, and claims priorityunder 35 U.S.C. § 120 to, U.S. patent application Ser. No. 10/404,867,filed on Apr. 1, 2003, which is incorporated herein by reference in itsentirety.

TECHNICAL FIELD

This invention relates to fastener elements useful for engaging loopsand the like.

BACKGROUND

Touch fasteners, such as hook and loop fasteners, generally include amale fastener component that includes a plurality of male fastenerelements, and a cooperating female fastener component. In general, themale fastener elements are adapted to engage loops or anchored fibers onthe female fastener component. Male fastener elements can be moldeddirectly into a desired shape or, alternatively, can be molded first andthen formed into a desired shape. Molded male fastener elementstypically are integrally formed with the base.

Some male fastener elements are in the shape of hooks. Each hookincludes a stem extending from the base to a head with a crook whichoverhangs the base. Typically, the hooks are molded in a continuousprocess, using a mold roll formed of a series of stacked plates, e.g.,as described in Fischer, U.S. Pat. No. 4,794,028, the disclosure ofwhich is incorporated herein by reference.

SUMMARY

In one aspect, the invention features a male fastener element extendingintegrally from a planar base. The fastener element includes a primaryengagement hook having a stem portion integrally molded with andextending from the planar base to a distal end, and an overhang portionextending from the distal end of the stem portion and having anunderside surface overhanging an open volume for receiving loops. Thefastener element also includes a secondary engagement structure disposedimmediately adjacent the primary engagement hook and extending from aside surface thereof. The secondary engagement structure is shorter thanthe primary engagement hook and extends from the base to a distal enddisposed, in side view, below the underside surface of the overhangportion of the primary engagement hook.

The primary engagement hook preferably has a height of between about0.005 inch and about 0.250 inch. The secondary engagement structurepreferably has a height of between about 0.003 inch and about 0.248inch. In some embodiments, the secondary engagement structure has aheight that is between about 1% and about 99% (e.g., between about 20%and about 80%) the height of the primary engagement hook.

The primary engagement hook preferably has a thickness of less thanabout 0.030 inch. The secondary engagement structure preferably has athickness of less than about 0.050 inch. In some cases, the secondaryengagement structure has a thickness that is between about 2% and aboutfifty times (e.g., between about 15% and about 8 times) the thickness ofthe primary engagement hook.

In some embodiments, a lowest part of the distal end of the primaryengagement hook and a highest part of the secondary engagement structuredefine between them a gap of a size selected to receive an engageablefiber of a mated loop material. The distance between the lowest part ofthe distal end of the primary engagement hook and the highest part ofthe secondary engagement structure is preferably at least about 0.001inch (e.g., between about 0.001 inch and about 0.248 inch).

The male fastener element can be formed of a polymeric material, forexample. In some embodiments, the male fastener element is of athermoplastic resin. The male fastener element preferably is molded of aresin from the following group: polyurethanes, polyolefins,polystyrenes, polycarbonates, polyesters, polymethacrylate, ethylenevinyl acetate copolymers, ethylene vinyl alcohol copolymers,polyvinylchloride, acrylate modified ethylene vinyl acetate polymers,and ethylene acrylic acid copolymers.

In some embodiments, the secondary engagement structure has a hook. Thesecondary engagement structure can include a palm-tree hook, forexample.

In some cases, the secondary engagement structure forms a diverter(e.g., a wedge-shaped structure), such as for diverting loops forimproved engagement.

In some cases, the secondary engagement structure defines a notch thatcan be useful for engaging a loop for better retention.

In some embodiments, the secondary engagement structure includes a knob.

In some cases, the primary engagement hook includes a palm-tree hook.The primary engagement hook can also be mushroom-shaped.

In some cases, the distal end of the secondary projection points towardthe planar base. In some other cases, the distal end of the secondaryprojection points away from the planar base.

Preferably, the entire secondary engagement structure is disposed, inside view, beneath the overhang portion of the primary engagement hook.It is also desirable, for some applications, that the secondaryengagement structure projects, in side view, outward beyond the overhangportion of the primary engagement hook.

In another aspect, the invention features a male fastener elementextending integrally from a planar base. The fastener element includes aprimary engagement hook that has a stem portion integrally molded withand extending from the planar base to a distal end, and an overhangportion extending from the distal end of the stem portion and having anunderside surface overhanging an open volume for receiving loops. Thefastener element also includes a secondary engagement structure disposedlaterally adjacent the primary engagement hook. The primary engagementhook and the secondary engagement structure define a lateral separationbetween them of between about 0.0005 inch and about 0.004 inch. Thesecondary engagement structure is shorter than the primary engagementhook and extends from the base to a distal end disposed, in side view,below the underside surface of the overhang portion of the primaryengagement hook.

In another aspect, the invention features a male fastener elementextending integrally from a planar base. The fastener element includes amolded, tapered primary stem extending integrally from the planar baseto a distal end. The fastener element also includes a secondaryengagement structure having a tapered stem portion integrally moldedwith the tapered primary stem and extending from the planar base to adistal end, and a tapered overhang portion extending from the distal endof the stem portion and having a first underside surface overhanging afirst open volume for receiving loops. The fastener element furtherincludes a second overhang portion disposed at the distal end of theprimary stem. The second overhang portion has a second underside surfaceoverhanging a second open volume for engaging loops. The second overhangportion extends, in side view, above the overhang portion of thesecondary engagement structure. The overhang portions of the secondaryengagement structure and the primary stem together overhang at most asingle, contiguous area of the base.

In another aspect, the invention features a method of making a malefastener element extending from a planar base. The method includesmolding a tapered primary stem extending integrally from the planar baseto a distal end. The method also includes molding a secondary engagementstructure including a tapered stem portion integrally molded with thetapered primary stem and extending from the planar base to a distal end,and a tapered overhang portion extending from the distal end of the stemportion and having a first underside surface overhanging a first openvolume for receiving loops. The method further includes forming a secondoverhang portion disposed at the distal end of the primary stem andhaving a second underside surface overhanging a second open volume forengaging loops, the second overhang portion extending, in side view,above the overhang portion of the secondary engagement structure. Theoverhang portions of the secondary engagement structure and the primarystem together overhang at most a single, contiguous area of the base.

In some embodiments, the primary stem portion and the secondaryengagement structure are both molded simultaneously in a contiguouscavity.

In some cases, the overhang portion forming step includes first heatingand then cooling the distal end of the primary stem portion.

The planar base is also laminated to another material for someapplications.

In another aspect, the invention features a method of making a malefastener element extending from a planar base. The method includesintegrally molding a primary stem portion extending from the planar baseand terminating in a distal end, forming a secondary engagementstructure, and forming an overhang portion extending from the distal endof the primary stem portion and having an underside surface overhangingan open volume for receiving loops. The secondary engagement structureis disposed immediately adjacent the primary stem portion and extendsfrom a side surface thereof. The secondary engagement structure isshorter than the primary stem portion and extends from the base to adistal end disposed, in side view, below the underside surface of theoverhang portion.

In some embodiments, the molding step includes extruding a resin into agap defined against a surface of a rotating mold roll, where the moldroll has discrete cavities extending inward from the surface.

In some cases, the secondary engagement structure forming step includesmolding. The primary stem portion and the secondary engagement structurecan be molded simultaneously in a contiguous cavity.

The overhang portion forming step in some embodiments includes firstheating and then cooling the distal end of the primary stem portion.

In another aspect, the invention features a molded male fastener elementextending integrally from a planar base. The fastener element includes aprimary engagement hook having a tapered stem portion integrally moldedwith and extending from the base to a distal end. A tapered overhangportion extends from the distal end of the stem portion and has anunderside surface overhanging the base for engaging loops. The fastenerelement also includes a secondary projection extending integrallyoutward from the stem portion of the primary engagement hook. Thesecondary projection is shorter than the primary engagement hook in adirection that is perpendicular to the base. The secondary projectionextends, in side view, below an underside surface of the overhangportion of the primary engagement hook.

The primary engagement hook preferably has a height of less than about0.250 inch. In some embodiments, the secondary projection extendsoutward from the stem portion of the primary engagement hook at aheight, relative to the planar base, of between about 1% and about 99%the height, relative to the planar base, of the primary engagement hook.

In some embodiments, the male fastener element is formed of a polymericmaterial. In some cases, the male fastener element is of a thermoplasticresin. The male fastener element preferably is formed of a resin fromthe following group: polyurethanes, polyolefins, polystyrenes,polycarbonates, polyesters, polymethacrylate, ethylene vinyl acetatecopolymers, ethylene vinyl alcohol copolymers, polyvinylchloride,acrylate modified ethylene vinyl acetate polymers, and ethylene acrylicacid copolymers.

The secondary projection can include a hook. In some cases, thesecondary projection extends outward from the stem portion of theprimary engagement hook in the direction of the planar base. In othercases cases, the secondary projection extends outward from the stemportion of the primary engagement hook in a direction away from theplanar base.

In another aspect, the invention features a method of making a malefastener element extending from a planar base. The method includesmolding a primary engagement hook having a tapered stem portionintegrally molded with and extending from the base to a distal end. Atapered overhang portion extends from the distal end of the stem portionand has an underside surface overhanging the base for engaging loops.The method also includes molding a secondary projection extendingintegrally outward from the stem portion of the primary engagement hook.The secondary projection is shorter than the primary engagement hook andextends, in side view, below an underside surface of the overhangportion of the primary engagement hook.

In some embodiments, the molding steps include extruding a resin into agap defined against a surface of a rotating mold roll. The mold rolldefines discrete cavities that extend inward from its surface.

Other aspects of the invention feature the above-described male fastenerelements engaged with, e.g., non-wovens, wovens, or knits. Furtheraspects of the invention feature the above-described male fastenerelements secured to articles such as diapers or other absorbentarticles, or medical, automotive, or industrial articles.

Implementations of the invention may have one or more of the followingadvantages. The male fastener elements may exhibit good engagementproperties. The male fastener elements may have more opportunities toengage a greater number of loops, relative to male fastener elementshaving only one engagement portion. An array of the male fastenerelements may engage loops having different lengths. When the malefastener elements are loaded in the cross-machine direction (e.g., whenthe male fastener elements are subjected to a shear force in thecross-machine direction), they may exhibit good resistance to bending.Once they have engaged loops, the male fastener elements may remain inengagement with those loops for a relatively long period of time.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features andadvantages of the invention will be apparent from the description anddrawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of one embodiment of a male fastenerelement.

FIG. 1A is a top view of the male fastener element of FIG. 1.

FIG. 1B is a front view of the male fastener element of FIGS. 1 and 1A.

FIG. 1C is a side view of the male fastener element of FIGS. 1-1B.

FIG. 1D is a side view of a second embodiment of a male fastenerelement.

FIGS. 2-2B diagrammatic perspective views that illustrate the engagementof the male fastener element of FIGS. 1-1C with loops.

FIG. 3 is a perspective view of a third embodiment of a male fastenerelement.

FIG. 3A is a perspective view of a fourth embodiment of a male fastenerelement.

FIG. 4 is a perspective view of a fifth embodiment of a male fastenerelement.

FIG. 4A is a side view of the male fastener element of FIG. 4.

FIG. 4B is a front view of the male fastener element of FIGS. 4 and 4A.

FIG. 5 is a schematic representation of a manufacturing process used tomake male fastener elements.

FIG. 5A is an enlarged partial perspective view of one embodiment of amold plate used in the process of FIG. 5.

FIG. 5B is an enlarged partial perspective view of a second embodimentof a mold plate used in the process of FIG. 5.

FIGS. 6-6C are perspective views of different embodiments of a malefastener element.

FIGS. 7-7D illustrate the engagement of the male fastener element ofFIG. 6A with loops.

FIGS. 8-8G are side views of embodiments of male fastener elements.

FIG. 9 is a side view of one embodiment of a male fastener element.

FIG. 10 is a schematic representation of a process used to make the malefastener element of FIG. 9.

FIGS. 10A and 10B are a schematic representation of the formation of themale fastener element of FIG. 9 by the process shown in FIG. 10.

FIGS. 1I and 1I A are side views of embodiments of a male fastenerelement.

FIGS. 12 and 12A are a schematic representation of the formation of amale fastener element.

DETAILED DESCRIPTION

Referring to FIG. 1, a male fastener component 8 includes a malefastener element 10 which extends integrally from a planar base sheet12. Although FIG. 1 shows just one male fastener element, an array ofmale fastener elements extending from a planar base may be used. Malefastener element 10 includes a primary engagement hook 14 and asecondary engagement structure 16. Primary engagement hook 14 has a stemportion 18 that is integrally molded with sheet 12. Stem portion 18extends from sheet 12 to a distal end 20. Primary engagement hook 14also has an overhang portion 22 that extends from distal end 20 and thathas an underside surface 24 overhanging an open volume 25. The overhangportion 22 can receive loops, as will be discussed below.

Secondary engagement structure 16 also extends integrally from planarbase sheet 12, and has a stem portion 26. In FIG. 1, the secondaryengagement structure 16 is located immediately adjacent primaryengagement hook 14, extending from a side surface 28 of the primaryengagement hook. However, in other embodiments of male fastener element10 (not shown), primary engagement hook 14 and secondary engagementstructure 16 are not immediately adjacent. Rather, they are separated bya space of between about 0.0005 inch and about 0.004 inch.

At its distal end, secondary engagement structure 16 has a head portion27. Although secondary engagement structure 16 is shown here as a hook,it can have other shapes in other embodiments of male fastener element10. FIG. 1A, a top view of male fastener element 10, shows that primaryengagement hook 14 and secondary engagement structure 16 share a commonsurface—i.e., that they are adjacent.

Referring back to FIG. 1, secondary engagement structure 16 is shorterthan primary engagement hook 14. In other words, the secondaryengagement structure is shorter than the primary engagement hook in adirection that is perpendicular to the base. In all embodiments, thesecondary engagement structure is shorter than the primary engagementhook. Additionally, in FIG. 1C, the length (L_(S)) of the secondaryengagement structure 16, i.e., the distance from the rear edge 15 of thebase of the secondary engagement structure 16 to the most forward point17 of its distal end, is less than the length (L_(p)) of primaryengagement hook 14 (measured in the same manner). When male fastenerelement 10 is viewed from the side, the secondary engagement structureappears to extend below the underside surface 24 of the primaryengagement hook. Secondary engagement structure 16 can also receiveloops, as will be shown below. Because of the ability of structure 16 toreceive loops, the overall engagement effectiveness of male fastenerelement 10 is generally enhanced relative to a similar male fastenerelement with only one engagement portion.

Referring now to FIG. 1B, a front view of male fastener element 10 isshown. As mentioned above, primary engagement hook 14 is taller thansecondary engagement structure 16. The primary engagement hookpreferably has a height H_(P) of between about 0.005 inch and about0.250 inch. The secondary engagement structure preferably has a heightHs of between about 0.003 inch and about 0.248 inch.

As shown in FIG. 1C, the distance D between the lowest part of thedistal end of primary engagement hook 14 and the highest part ofsecondary engagement structure 16 is wide enough to receive, e.g., anengageable fiber of a mated loop material. Distance D is between about0.001 inch and about 0.247 inch, e.g., between about 0.001 inch andabout 0.010 inch.

Referring back to FIG. 1B, primary engagement hook 14 preferably has athickness T_(P) of between about 0.001 inch and about 0.050 inch, whilesecondary engagement structure 16 preferably has a thickness T_(S) ofbetween about 0.001 inch and about 0.050 inch. The secondary engagementstructure may have the same thickness as the primary engagement hook, orthe engagement structure and the hook may have different thicknesses.The thickness of the secondary engagement structure can be between about2% and about 5000% the thickness of the primary engagement hook (e.g.,between about 15% and about 800% the thickness of the primary engagementhook, between about 25% and about 75% the thickness of the primaryengagement hook).

Referring back to FIG. 1, the primary engagement hook and the secondaryengagement structure both have base widths that are defined as thewidths of their stem portions taken parallel to base sheet 12 at thelevel where the stem portions join the base sheet. In other words,primary engagement hook 14 has a base width B_(P) that preferably isbetween about 0.005 inch and about 0.100 inch. Secondary engagementstructure 16 has a base width B_(S) that preferably is between about0.005 inch and about 0.100 inch. In some embodiments, B_(S)=B_(P).

Male fastener element 10 is preferably made of polymers such asthermoplastic materials, including polyurethanes, polyolefins (e.g.,polypropylene, polyethylene), polystyrenes, polycarbonates, polyesters,polymethacrylate, ethylene vinyl acetate copolymers, ethylene vinylalcohol copolymers, polyvinylchloride, acrylate modified ethylene vinylacetate polymers, and ethylene acrylic acid copolymers.

FIG. 1C shows a male fastener element 10 with a secondary engagementstructure 16 that appears to extend, in side view, entirely beneath theunderside surface 24 of primary engagement hook 14. In other words, inFIG. 11C, the secondary engagement structure does not appear to extend,in side view, beyond underside surface 24. However, as FIG. 1D shows, insome embodiments the secondary engagement structure 16 may appear toextend, in side view, beyond the underside surface 24 of primaryengagement hook 14. In FIG. 1D, the secondary engagement structure alsois shorter than the primary engagement hook in a direction that isperpendicular to the base. Other embodiments of a male fastener element,shown below, may also have this alternative structure, i.e. with thesecondary engagement structure appearing to extend beyond the undersidesurface of the primary engagement structure in side view.

Referring now to FIGS. 2-2B, male fastener component 8 includes a malefastener element 10, constructed to engage loops 30 of a female fastenercomponent 31. (In FIGS. 2-2B, only one male fastener element 10 isshown; however, in practice, male fastener component 8 generallyincludes an array of male fastener elements 10.) Because male fastenerelement 10 has two engagement portions of different heights, malefastener element 10 can generally engage loops having a range ofdifferent lengths, as shown in FIGS. 2-2B.

Another advantage of male fastener element 10 is that it may have moresuccess in engaging individual loops than would a male fastener elementwith just one engagement portion. That is, secondary engagementstructure 16 may initially engage a loop 30, but then may lose itsengagement with the loop. However, primary engagement hook 14 may engagethe loop as it is disengaging from the secondary engagement structure.Thus, by having two engagement portions in close proximity to eachother, male fastener element 10 may exhibit enhanced engagement of loopsas compared to other male fastener elements that lack such a feature.

Alternatively, a loop 30 may engage with both primary engagement hook 14and secondary engagement structure 16, such that the loop wraps aroundthe whole of male fastener element 10. Thus, if the loop starts to peelaway from the male fastener element, the male fastener element's twoengagement portions may make it more difficult for the loop tosuccessfully disengage from the male fastener element (as compared tothe disengagement of a loop from a male fastener element with just oneengagement portion). Additionally, a loop engaged with such a malefastener element may experience enhanced friction when it is pulled inthe cross-machine direction, relative to a loop engaged with a malefastener element having just one engagement portion. Furthermore, themale fastener element 10 may be relatively resistant to bending when theengaged loop is pulled in the cross-machine direction.

Referring now to FIG. 3, a male fastener element 40 has a primaryengagement hook 42 and two secondary engagement structures, 44 and 46.Male fastener element 40 is similar to male fastener element 10 of FIG.1, the only significant difference being that fastener element 40 hastwo secondary engagement structures, while fastener element 10 only hasone. In FIG. 3, secondary engagement structures 44 and 46 are shorterthan primary engagement hook 42. Alternatively, as shown in FIG. 3A, amale fastener element 41 has two primary engagement hooks, 45 and 47,and a secondary engagement structure 49. Secondary engagement structures44, 46, and 49 preferably have a height of between about 0.003 inch andabout 0.248 inch, and a thickness of between about 0.001 inch and about0.030 inch. The base width of secondary engagement structures 44, 46,and 49 preferably is between about 0.005 inch and about 0.100 inch.Primary engagement hooks 42, 45, and 47 preferably have a height ofbetween about 0.005 inch and about 0.250 inch, and a thickness ofbetween about 0.001 inch and about 0.030 inch. The base width of primaryengagement hooks 42, 45, and 47 preferably is between about 0.005 inchand about 0.100 inch. The secondary engagement structures may have thesame size (i.e., height, width, etc.), or alternatively, they may havedifferent sizes. The secondary engagement structures may have the samethickness as the primary engagement hooks, or may be of a differentthickness from the primary engagement hooks.

Referring now to FIG. 4, a male fastener element 50 extends integrallyfrom a planar base sheet 52. Male fastener element 50 includes a primaryengagement hook 54 and a secondary projection 56. Male fastener element50 has a tapered stem portion 58 that is integrally molded with planarbase sheet 52. Stem portion 58 extends from base sheet 52 to a distalend 60. Primary engagement hook 54 also has a tapered overhang portion62 that extends from distal end 60 and that has an underside surface 64overhanging an open volume 67. Overhang portion 62 can receive loops.Secondary projection 56 extends integrally outward from stem portion 58,and, as FIG. 4A shows, has a shorter length (L_(S2)) than does primaryengagement hook 54 (L_(P2)). Secondary projection 56 extends belowunderside surface 64 of overhang portion 62 of primary engagement hook54. In FIG. 4A, the secondary projection extends entirely beneath theunderside surface of the primary engagement hook. However, as notedabove, in some embodiments the secondary projection may extend beyondthe underside surface of the primary engagement hook.

Referring now to FIG. 4B, male fastener element 50 preferably has aheight HF Of between about 0.005 inch and about 0.250 inch, and athickness T_(F) of between about 0.001 inch and about 0.030 inch.Referring back to FIG. 4, male fastener element 50 preferably has a basewidth B_(F) of between about 0.005 inch and about 0.100 inch. Malefastener element 50 preferably is made of polymers such as thermoplasticmaterials, including polyurethanes, polyolefins (e.g., polypropylene,polyethylene), polystyrenes, polycarbonates, polyesters,polymethacrylate, ethylene vinyl acetate copolymers, ethylene vinylalcohol copolymers, polyvinylchloride, acrylate modified ethylene vinylacetate polymers, and ethylene acrylic acid copolymers.

Because male fastener element 50 has two engaging portions, i.e.,primary engagement hook 54 and secondary projection 56, male fastenerelement 50 has enhanced engagement capabilities relative to a fastenerelement having only one engaging portion. When male fastener element 50receives a loop, it can receive the loop on either of its two engagingportions. If, for example, fastener element 50 receives a loop on itssecondary projection 56, and then the loop slides off, there is stillthe possibility that primary engagement hook 54 may engage the loop asit is being pulled away. On the other hand, if fastener element 50receives a loop on its primary engagement portion, then the loop isprotected somewhat from disengagement by being loosely “locked” into thespace between the primary engagement hook and the secondary projection.Thus, fastener element 50 may exhibit better binding than a fastenerelement with only one engaging portion. Furthermore, male fastenerelement 50 may be better protected against shear in the cross-machinedirection, relative to a male fastener element having only oneengagement portion. Because male fastener element 50 has two engagementportions, it allows for more opportunity for friction between it and theengaged loop.

The secondary projection 56 of male fastener element 50 may take any oneof a number of different shapes. For example, the secondary projectionmay protrude straight out from stem portion 58. It may slant in anupward direction or in a downward direction. The secondary projectionmay be a hook, and may curve generally upward or generally downward. Theshape of the secondary projection may depend on its desired properties.

FIG. 5 shows a process for making the above male fastener elements usingan extrusion apparatus 100. Suitable processes are described, e.g., inFischer, U.S. Pat. No. 4,794,028. Extrusion apparatus 100 includes amolding/calendaring assembly 102, which further includes an extruderbarrel 104, a slot-form die 106, a base roll 108, a mold roll 110, atake-off roll 112, and a guide roll 114. Using a continuous process,molten resin is extruded and applied with pressure against the cooledmold roll 110, which has mold cavities about its periphery that areconfigured to produce fastener elements 115. A suitable mold roll 110 isdescribed below, with reference to FIG. 5A.

In use, extruder barrel 104 melts a plastic resin and forces the moltenplastic through slot-form die 106, to form a sheet-form extrudate ofmolten plastic 116. The extruded plastic 116, while still molten, entersa nip 118 formed between base roll 108 and mold roll 110. As describedin U.S. Pat. No. 4,794,028, due to pressure applied at the nip by rolls108 and 110, molten resin is forced into cavities 120, forming thefastener elements 115. The molded fastener elements are on a sheet-formbase 119.

In some cases, roll 113 may be used for, e.g., laminating a substrate tothe sheet-form base as the sheet-form base is being made. For example,preformed material, woven material, stretchable fabric, or film can belaminated onto the sheet-form base. A suitable lamination process isdescribed in U.S. Pat. No. 6,174,476 (Kennedy et al.), the entirecontents of which are herein incorporated by reference. In some cases, aloop material may be laminated onto the base, as described in U.S. Ser.No. 09/808,395, published on Feb. 21, 2002 as U.S. Patent ApplicationPublication No. U.S. 2002/0022108 A1, the entire contents of which areherein incorporated by reference.

Referring now to FIGS. 5A and 5B, mold plates used in the aboveextrusion apparatus have different configurations, depending on thedesired shape of the fastener element to be formed. For example,referring to FIG. 5A, mold plates 200 and 202 can be used together toform male fastener element 10 of FIG. 1. Mold plate 200 defines a cavity204 (in part shown by phantom lines) in which primary engagement hook 14can be formed when molten resin enters the cavity. Mold plate 202defines a cavity 206 in which secondary engagement structure 16 can beformed when molten resin enters the cavity. When used in extrusionapparatus 100, mold plates 200 and 202 are placed immediately adjacenteach other so that the primary engagement hook and secondary engagementstructure will be integrally molded adjacent to each other, therebyforming male fastener element 10.

To form fastener elements in which the primary engagement structure isnot immediately adjacent to the secondary engagement structure, a spacerplate can be inserted between the mold plates during processing.

Referring now to FIG. 5B, a mold plate 208 is shown that can be used tomake male fastener element 50 of FIG. 4. Mold plate 208 defines a cavity210 having a deeper and broader portion 212 for forming the primaryengagement hook 54 of male fastener element 50, and a shallower andsmaller portion 214 for forming the secondary projection 56 of malefastener element 50.

Referring now to FIG. 6, a male fastener element 300 extends integrallyfrom a planar base sheet 302. Male fastener element 300 is similar tomale fastener element 10 of FIG. 1, with the exception that thesecondary engagement structure 304 of fastener element 300 is a diverter(here, a wedge-shaped diverter). By “diverter,” we mean to say astructure that diverts loops from loop-engageable material towardpossible engagement with a male fastener element.

As with fastener element 10, secondary engagement structure 304 offastener element 300 is integrally molded to a side 306 of a primaryengagement hook 308. Secondary engagement structure 304 may assist theprimary engagement hook in engaging a loop by further opening the loop,for example, or by temporarily trapping the loop until the loop slidesup a side of the secondary engagement structure and is engaged by theprimary engagement hook. In some cases, as shown in FIG. 6B, secondaryengagement structure 304 may be adjacent to a greater portion of side306 than it is in FIG. 6. Such an embodiment of male fastener element300 may exhibit even more strength and resistance to bending in thecross-machine direction than, for example, the embodiment shown in FIG.6.

While the secondary engagement structure of male fastener element 300can be wedge-shaped, it can also be in the shape of a wedge with anotched side. Referring now to FIG. 6A, a male fastener element 350includes a wedge-shaped secondary engagement structure 352 with anotched side 354. The secondary engagement structure 352 is integrallymolded to a side 356 of a primary engagement hook 358.

The notched side can lead to even better loop engagement success.Referring now to FIGS. 7-7D, male fastener element 350 engages a loop257. In FIGS. 7 and 7A, loop 257 slides by primary engagement hook 358,such that it begins to slide over the crook 360 of hook 358. In FIGS. 7Band 7C, the primary engagement hook has engaged the loop. In FIG. 7D, asthe loop is pulled in the opposite direction, it has disengaged from theprimary engagement hook. However, the loop is prevented from disengagingfrom male fastener element 350 altogether because the notched side 354of the secondary engagement structure 352 has trapped the loop onceagain. Thus, the notched side decreases the likelihood of loopdisengagement by essentially giving the male fastener element a “secondchance” to reengage a loop once it has started to disengage.Furthermore, in some embodiments the wedge can add support to theprimary engagement hook in the cross-machine direction.

In some cases, as shown in FIG. 6C, a male fastener element 370 includesa primary engagement hook 372 and a wedge-shaped diverter 374 with aknob or knobs 376 on its side. The knobs create added friction for aloop in contact with diverter 374, and give male fastener element 370good engagement capability.

FIG. 11 shows a male fastener element 700 that includes a primaryengagement palm tree hook 702, and a secondary engagement structure 704(here, a hook). The secondary engagement structure 704 is integrallymolded to a side 706 of a primary engagement palm tree hook 702. Asshown in FIG. 11A, in some embodiments, the secondary engagementstructure 704 may be a palm tree hook, as well.

Referring now to FIGS. 8-8G, male fastener element 10 has many differentpossible embodiments. In different embodiments, the secondary engagementstructures can be oriented at different angles and can have differentshapes. The secondary engagement structure 16 of male fastener element10 can project horizontally outward, for example, as shown in FIG. 8.Alternatively, structure 16 can project in a diagonal upward direction,as shown in FIG. 8A. In FIG. 8B, structure 16 points upward, but curvesslightly at its distal end. FIG. 8C shows a structure 16 pointing in anupward direction, and becoming relatively narrow at its distal end. Inother embodiments, structure 16 can be in the shape of a hook, as inFIG. 8D. In FIG. 8E, the secondary engagement structure 16 points in asteep upward direction, and is narrower at its base than it is in someof the other embodiments. In FIG. 8F, secondary engagement structure 16is in the shape of a hook, and is adjacent to a relatively large portionof the side of primary engagement hook 14. Finally, in FIG. 8G,secondary engagement structure 16 curves upward in a short hook.

The above embodiments can have various advantages relative to a similarmale fastener element with only one engagement structure. For example,the above embodiments can have some or all of the following advantages:increased opportunity to engage more loops of varying lengths, increasedcross-machine direction shear, increased machine direction peel,enhanced cross-machine direction peel, increased opportunity to lock inloops under the primary engagement hook, and increased stiffness of theprimary engagement hook in the cross-machine direction. Moreover, any ofthe embodiments shown and discussed above can include a re-entrant hookgeometry, which will tend to enhance engagement with loops.

Referring now to FIG. 9, a male fastener element 400 includes aflat-topped mushroom 402 and a secondary engagement structure 404, bothof which are configured to receive loops. Mushroom 402 has a stemportion 406 that is integrally molded with a planar base sheet 408. Stemportion 406 extends from sheet 408 to a distal end 410. Mushroom 402also has a generally disc-shaped head 412 that extends from distal end410 and overhangs base sheet 408. A portion of head 412 has an undersidesurface 414 overhanging an open volume 416.

Secondary engagement structure 404 extends integrally from planar basesheet 408, as well, and has a stem portion 418. The secondary engagementstructure is located immediately adjacent mushroom 402, extending from aside surface 420 of the primary engagement mushroom. However, for someapplications, the secondary engagement structure and the primaryengagement structure are not immediately adjacent, but are separated bya space of between about 0.0005 inch and about 0.004 inch. Suchseparation can be provided, for example, by placing a spacer ringbetween the mold rings that are used to form male fastener element 400.Secondary engagement structure 404 is shorter than mushroom 402.Additionally, secondary engagement structure 404 has a shorter length(L_(S3)) than does mushroom 402 (L_(P3)). Thus, when male fastenerelement 400 is viewed from the side, the secondary engagement structure404 extends below the underside surface 414 of the head 412. In someembodiments, the secondary engagement structure extends beyond theprimary engagement structure.

Male fastener element 400 exhibits good engagement capacity.Additionally, the flat-topped mushroom 402 of male fastener element 400may be softer to the touch than a regular hook of comparable size. Thus,male fastener element 400 is well-suited for applications in which it isdesirable to have enhanced loop-engaging capacity in combination withrelatively soft engagement material. Male fastener element 400 is alsowell-suited for skin-friendly applications. While FIG. 9 shows aflat-topped mushroom, male fastener element 400 can, in someembodiments, include, e.g., a flat-topped hook or a flat-topped steminstead.

Referring now to FIG. 10, a mold-roll apparatus 500 can be used to makemale fastener element 400. Apparatus 500 includes an extruder 502, apressure roll 504, a mold roll 506, a wrap-around roller 508, and aknock-down roller 510. To make male fastener elements, molten resin 512from extruder 502 is continuously extruded into a nip 514 formed betweencooled mold roll 506 and pressure roll 504. Under the pressure of thenip, molten resin is forced into mold cavities 516 and also between therolls, to form a sheet-form base 517 that is integral with the moldedfastener formations 400. Thereafter, the molded tape 518 is passedbetween wrap-around roller 508 and knock-down roller 510 while thefastener elements are still soft and permanently deformable. Roller 510pushes any higher elements down to a uniform, desired pre-establishedheight. During this process, therefore, the flat-topped mushrooms may beformed from a molded element (see further discussion below, withreference to FIG. 10B). In other instances, the knock-down roller 510 isheated to a level sufficient to enable it to reform, by thermoforming,the engaged portion of the molded elements to provide furthercharacteristics to the end product.

A method for flat-topping mushrooms is disclosed in U.S. Pat. No.6,248,276 (Parellada et al.), the entire contents of which are hereinincorporated by reference. A method for flat-topping stems or hooks isdescribed in U.S. Pat. No. 5,953,797 (Provost et al.), the entirecontents of which are herein incorporated by reference.

Referring now to FIGS. 10A and 10B, male fastener element 400 is createdby a deformation process under the knock-down roller 510 discussed withreference to FIG. 10. In FIG. 10A, a molded structure 600 and secondaryengagement structure 404 have been molded according to the processgenerally described with reference to FIG. 5. The structures 600 and 404have yet to come into contact with the force of knock-down roller 510.In FIG. 10B, however, the knock-down roller has come into contact withmolded structure 600, deforming the top of the molded structure andforming male fastener element 400.

As discussed above with reference to FIG. 9, some embodiments of malefastener element 400 may include flat-topped hooks. Referring now toFIGS. 12 and 12A, such a male fastener element 400 is created by adeformation process under the knock-down roller 510 discussed withreference to FIG. 10. In FIG. 12, a J-hook 800 and secondary engagementstructure 804 have been molded according to the process generallydescribed with reference to FIG. 5. The structures 800 and 804 have yetto come into contact with knock-down roller 510. In FIG. 12A, however,the knock-down roller has come into contact with molded structure 800,deforming the top of the structure to form male fastener element 400.

Further embodiments are within the following claims.

1. A male fastener element extending integrally from a planar base, thefastener element comprising: a primary engagement hook comprising a stemportion integrally molded with and extending from the planar base to adistal end; and an overhang portion extending from the distal end of thestem portion and having an underside surface overhanging an open volumefor receiving loops; and a secondary engagement structure disposedimmediately adjacent the primary engagement hook and extending from aside surface thereof, wherein the secondary engagement structure isshorter than the primary engagement hook and extends from the base to adistal end disposed, in side view, below the underside surface of theoverhang portion of the primary engagement hook.
 2. The male fastenerelement of claim 1, wherein the primary engagement hook has a height ofbetween about 0.005 inch and about 0.250 inch.
 3. The male fastenerelement of claim 1, wherein the secondary engagement structure has aheight of between about 0.003 inch and about 0.248 inch.
 4. The malefastener element of claim 1, wherein the secondary engagement structurehas a height that is between about 1% and about 99% the height of theprimary engagement hook.
 5. The male fastener element of claim 4,wherein the secondary engagement structure has a height that is betweenabout 20% and about 80% the height of the primary engagement hook. 6.The male fastener element of claim 1, wherein the primary engagementhook has a thickness of less than about 0.030 inch.
 7. The male fastenerelement of claim 1, wherein the secondary engagement structure has athickness of less than about 0.050 inch.
 8. The male fastener element ofclaim 1, wherein the secondary engagement structure has a thickness thatis between about 2% and about 5000% the thickness of the primaryengagement hook.
 9. The male fastener element of claim 8, wherein thesecondary engagement structure has a thickness that is between about 15%and about 800% the thickness of the primary engagement hook.
 10. Themale fastener element of claim 1, wherein a lowest part of the distalend of the primary engagement hook and a highest part of the secondaryengagement structure define therebetween a gap of a size selected toreceive an engageable fiber of a mated loop material.
 11. The malefastener element of claim 10, wherein the distance between the lowestpart of the distal end of the primary engagement hook and the highestpart of the secondary engagement structure is at least about 0.001 inch.12. The male fastener element of claim 11, wherein the distance betweenthe lowest part of the distal end of the primary engagement hook and thehighest part of the secondary engagement structure is between about0.001 inch and about 0.248 inch.
 13. The male fastener element of claim1, further comprising a polymer.
 14. The male fastener element of claim13, wherein the polymer comprises a thermoplastic resin.
 15. The malefastener element of claim 14, wherein the resin is selected from thegroup consisting of polyurethanes, polyolefins, polystyrenes,polycarbonates, polyesters, polymethacrylate, ethylene vinyl acetatecopolymers, ethylene vinyl alcohol copolymers, polyvinylchloride,acrylate modified ethylene vinyl acetate polymers, and ethylene acrylicacid copolymers.
 16. The male fastener element of claim 1, wherein thesecondary engagement structure comprises a hook. 17-23. (canceled) 24.The male fastener element of claim 1, wherein the distal end of thesecondary projection points toward the planar base.
 25. (canceled) 26.The male fastener element of claim 1, wherein the entire secondaryengagement structure is disposed, in side view, beneath the overhangportion of the primary engagement hook. 27-49. (canceled)